Adhesive shock absorber

ABSTRACT

Bolted mounting assemblies for use between two mounted components wherein one of the components experiences vibration typically use rubber shock absorbers to dampen the vibration transfer between the components. The rubber shock absorbers are expensive and complicated to manufacture and are limited in flexibility control. The present invention overcomes this and other problems by providing an adhesive with damping capabilities between washers in a bolt assembly. The bolt assembly is used to mount first and second components with the washers therebetween. The adhesive is spaced a predetermined distance from a longitudinal axis of a bolt and has a non-uniform thickness which increases as the distance from the longitudinal axis increases to provide protection from bending loads about the axis. The washers with adhesive form a washer assembly with damping and flexibility characteristics controlled through variations in the design. The washer assembly provides a simple, inexpensive shock absorber between two components which experience vibration to substantially eliminate vibration transfer therebetween.

This is a divisional application of application Ser. No. 08/813,221,filed Mar. 7, 1997, of STEPHANE L. MANDON for ADHESIVE SHOCK ABSORBER.

TECHNICAL FIELD

This invention relates generally to a bolted mounting assembly betweentwo components and more particularly to an energy absorbing adhesivewithin the bolted mounting assembly which minimizes vibration transferbetween the components.

BACKGROUND ART

Bolted assemblies may be used between two mounted components, such as aframe and an enclosure, on a construction machine. Typically, thesemounted components must withstand substantial vibration occurringtherebetween which produces axial and bending loads. Therefore, anelastomeric material, such as a rubber shock absorber, is used inconjunction with the bolted assembly to reduce the vibration transferfrom one component to the other. Unfortunately, significantmanufacturing costs are incurred in utilizing the rubber shock absorbersdue to the necessary tooling and mold requirements of producingelastomeric materials. Additionally, rubber shock absorbers often aretoo flexible between the components, lowering the natural frequency ofthe component which limits the vibration control of the rubber shockabsorbers. Furthermore, the increased use of composites in constructionmachine components increases the need to control the vibration transfertherebetween in order to prolong the life of the composite material.

An example of a damping material used between a metallic constrainingplate and a vibration source is disclosed in U.S. Pat. No. 5,300,355issued to Naoto Mifune et al. on Apr. 5, 1994. This design relates toutilization of a magnetic composite type damping material constructed bybonding an adhesive elastic sheet containing magnetic powder to aconstraining plate such as a metal plate by using an adhesive composedof rubber elastomer, adhesive resin, plasticizer, magnetic powder, etc.The design of Mifune et al. is attracted by magnetic force against avibration source and exhibits vibration damping properties in a widetemperature range due to the synergism of the magnetic and adheringforces. The design of Mifune et al. is utilized between two planarcomponents to mainly control shear loads and vibration concernstherefrom. The damping material would not be preferable in anenvironment which includes axial and bending loads. Additionally, thedesign of Mifune et al. would not be used with a bolted mountingassembly since the adhesive elastic sheet utilized produces a clampingeffect without any mechanical devices, such as a bolt. The clampingeffect of the adhesive elastic sheet would generally not withstand largestresses and would not provide the high torque requirements necessary onmounted components on a construction machine.

The present invention is directed to overcoming the problems as setforth above.

DISCLOSURE OF THE INVENTION

In one aspect of the present invention, an energy absorbing assemblymounts first and second components. The first component has upper andlower surfaces which define an opening therethrough. The secondcomponent has an upper surface which defines an opening extendingtherein. The opening in the first component is positioned coaxially withthe opening in the second component. A first member has substantiallyplanar upper and lower surfaces which define an opening therethrough.The upper surface of the first member is positioned adjacent the lowersurface of the first component with the opening of the first membercoaxial with the opening of the first component. A second member hasupper and lower surfaces which define an opening therethrough. A firstpredetermined portion of the upper surface of the second member divergesoutwardly toward the lower surface of the second member to define aspace between the lower surface of the first member and the firstportion of the upper surface of the second member. A second portion ofthe upper surface of the second member is positioned adjacent the lowersurface of first member and the lower surface of the second member ispositioned adjacent the upper surface of the second component. Theopening of the second member is coaxial with the opening of the secondcomponent. A threaded fastener has a longitudinal axis, an elongatedbody portion which extends through the openings in the first component,the first member and the second member and into the opening within thesecond component and a head portion seated against the upper surface ofthe first component. An adhesive is disposed within the space betweenthe lower surface of the first member and the first portion of the uppersurface of the second member.

In another aspect of the present invention, a bolt assembly includes aflat washer which has upper and lower planar surfaces defining anopening therethrough. A bevel washer has upper and lower surfaces whichdefine an opening therethrough and is positioned with a first planarportion of the upper surface of the bevel washer adjacent the lowersurface of the flat washer. A second portion of the upper surface of thebevel washer diverges outwardly a predetermined distance toward thelower surface of the bevel washer to define a space between the lowersurface of the flat washer and the second portion of the upper surfaceof the bevel washer. The opening of the bevel washer is coaxial with theopening of the flat washer. A bolt has a longitudinal axis, an elongatedbody portion which extends through the openings in the flat washer andthe bevel washer and a head portion seated against the upper surface ofthe flat washer. An adhesive is disposed within the space between thelower surface of the flat washer and the second portion of the uppersurface of the bevel washer.

In yet another aspect of the present invention, a washer assemblyincludes a flat washer which has upper and lower planar surfacesdefining an opening therethrough. A bevel washer has upper and lowersurfaces which define an opening therethrough and is positioned with afirst planar portion of the upper surface of the bevel washer adjacentthe lower surface of the flat washer. A second portion of the uppersurface of the bevel washer diverges outwardly a predetermined distancetoward the lower surface of the bevel washer to define a space betweenthe lower surface of the flat washer and the second portion of the uppersurface of the bevel washer. The opening of the bevel washer is coaxialwith the opening of the flat washer. An adhesive is disposed within thespace between the lower surface of the flat washer and the secondportion of the upper surface of the bevel washer.

In yet another aspect of the present invention, a method of mountingfirst and second components to substantially eliminate vibrationtransfer therebetween is disclosed. The first step is to apply anadhesive to a first inclined portion of an upper surface of a bevelwasher. Next, attach a flat washer which defines an opening therethroughat a first portion of a lower surface to a second planar portion of theupper surface of the bevel washer which defines an opening therethroughso that a second portion of the lower surface of the flat washer is incontact with the adhesive and the openings of the bevel washer and theflat washer are coaxially aligned. Then, allow the adhesive to curebetween the second portion of the lower surface of the flat washer andthe first portion of the upper surface of the bevel washer to bind theflat washer and the bevel washer together thereby defining the washerassembly which defines a joint opening therethrough. Next, place thewasher assembly on an upper surface of the second component so that thejoint opening of the washer assembly is coaxially aligned with a definedopening within the second component. Then, align a lower surface of thefirst component with the upper surface of the second component andcontact the lower surface of the first component with an upper surfaceof the washer assembly so that a defined opening through the firstcomponent is coaxially aligned with the joint opening in the washerassembly and the opening within the second component. Then, threading anelongated body portion of a fastener with a longitudinal axis throughthe openings of the first component and the washer assembly and into theopening within the second component until a head portion of the fastenerseats against a portion of an upper surface of the first component andthe first component, second component and washer assembly are securelyattached. Next, vibrating the second component. Finally, damping thevibration from the second component within the adhesive in the washerassembly so that vibration from the second component is substantiallynot transferred to the first component.

The present invention, through the use of a energy absorbing assemblywhich is simple and easy to manufacture, provides a means forsubstantially eliminating vibration transfer between two mountedcomponents.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a frame assembly for a constructionmachine embodying the present invention;

FIG. 2 is an enlarged section view taken along line 2--2 of FIG. 1;

FIG. 3 is a section view taken along line 3--3 of FIG. 2;

FIG. 4 is a three dimensional view of a washer portion of the presentinvention; and

FIG. 5 is a three dimensional view of a washer portion of an alternateembodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

A structural assembly 10 for a construction machine (not shown) with aframe assembly 14 and a hood assembly 18 is shown in FIG. 1. Although aframe assembly 14 and hood assembly 18 are used in conjunction with thepresent invention, it should be understood that any mounted componentsmay be utilized. The frame assembly 14 has upper and lower surfaces22,26. A tapped bore 30 is defined from the upper surface 22 and extendsa predetermined distance into the frame assembly 14. The hood assembly18 has a mounting flange 32 with upper and lower surfaces 34,38 whichdefine a hole 42 therethrough. A method of mounting 44 the hood assembly18 and the frame assembly 14 is provided through the use of a boltassembly 46. The lower surface 34 of the hood assembly 14 is mounted inclose proximity to the upper surface 22 of the frame assembly 14. Thebolt assembly 46 passes through the hole 42 of the mounting flange 32and into the bore 30 within the frame assembly 14. The hole 42 in themounting flange 32 is substantially coaxially aligned with the tappedbore 30 within the frame assembly 14 prior to mounting.

Referring more specifically to FIGS. 2-5, the bolt assembly 46 includesa threaded bolt 50 of any suitable type and a washer assembly 54. Thebolt 50 has a head portion 58 and an elongated body 62 extending fromthe head portion with a portion 66 thereof being threaded. The bolt 50has a longitudinal axis 70 passing therethrough. The washer assembly 54is positioned between the frame assembly 14 and the hood assembly 18 andhas an opening 74 therethrough substantially coaxially aligned with thetapped bore 30 within the frame assembly 14 and hole 42 in the mountingflange 32 of the hood assembly 18. The elongated body 62 of the bolt 50passes through the hole 42 in the mounting flange 32 and the opening 74through the washer assembly 54 with the threaded portion 66 threadedinto the tapped bore 30 within the frame assembly 14 in a conventionalmanner for tightening the head portion 58 of the bolt 50 against theupper surface 34 of the mounting flange 32.

The washer assembly 54 includes a flat metallic washer 80 of anysuitable type, including any geometrical shape as shown morespecifically in FIG. 5. The flat washer 80 has upper and lower planarsurfaces 84,88 with an opening 92 defined therethrough. A first metallicbevel washer 96 of any suitable type, including any geometrical shape asshown more specifically in FIG. 5, has an upper surface 100 and a lowerplanar surface 104. A first portion 108 of the upper surface 100 and thelower planar surface 104 of the first bevel washer 96 define an opening112 therethrough. The first portion 108 of the upper surface 100 of thefirst bevel washer 96 is planar and extends a predetermined distancefrom the longitudinal axis 70 of the bolt 50. The first portion 108 ofthe upper surface 100 of the first bevel washer 96 is adjacent and incontact with a first portion 114 of the lower planar surface 88 of theflat washer 80 so that the opening 112 of the first bevel washer 96 iscoaxially aligned with the opening 92 of the flat washer 80. A secondportion 116 of the upper surface 100 of the first bevel washer 96diverges outwardly a predetermined distance and angle from the firstportion 108 of the upper surface 100 of the first bevel washer 96 towardthe lower planar surface 104 of the first bevel washer 96. It should beunderstood that the second portion 116 may be inclined from 20 to 40degrees from the first portion 108. A first space 120 is defined betweena second portion 122 of the lower planar surface 88 of the flat washer80 and the second portion 116 of the upper surface 100 of the firstbevel washer 96. An energy absorbing adhesive 124, such as epoxy mono orbicomponent, with a substantial temperature range from -55 C. to +120C., an approximate shear capacity of around 20 Mpa and a densityapproaching 1.1 to 1.3 is disposed on the second portion 116 of theupper surface 100 of the first bevel washer 96 to substantially enclosethe space 120 and is attached to the second portion 122 of the lowerplanar surface 88 of the flat washer 80. The adhesive 124 is spaced apredetermined distance from the longitudinal axis 70 of the bolt 50. Asecond metallic bevel washer 128 of any suitable type, including anygeometrical shape as shown more specifically in FIG. 5, has an uppersurface 132 and a lower planar surface 136. A first portion 140 of theupper surface 132 and the lower planar surface 136 of the second bevelwasher 128 define an opening 144 therethrough. The first portion 140 ofthe upper surface 132 of the second bevel washer 128 is planar andextends a predetermined distance from the longitudinal axis 70 of thebolt 50. The first portion 140 of the upper surface 132 of the secondbevel washer 128 is adjacent and in contact with a first portion 146 ofthe lower planar surface 104 of the first bevel washer 96 so that theopening 144 of the second bevel washer 128 is coaxially aligned with theopening 112 of the first bevel washer 96. A second portion 150 of theupper surface 132 of the second bevel washer 128 diverges outwardly apredetermined distance and angle from the first portion 140 of the uppersurface 132 of the second bevel washer 128 toward the lower planarsurface 136 of the second bevel washer 128. It should be understood thatthe second portion 150 may be inclined from 20 to 40 degrees from thefirst portion 140. A second space 154 is defined between a secondportion 156 of the lower planar surface 104 of the first bevel washer 96and the second portion 150 of the upper surface 132 of the second bevelwasher 128. The energy absorbing adhesive 124 used in the first space120 or of any suitable type is disposed on the second portion 150 of theupper surface 132 of the second bevel washer 128 to substantiallyenclose the second space 154 and is attached to the second portion 156of the lower planar surface 104 of the first bevel washer 96. Theadhesive 124 is spaced a predetermined distance from the longitudinalaxis 70 of the bolt 50. It should be understood that the washer assembly54 may include successive bevel washers and adhesive as is needed toobtain optimal flexibility characteristics.

INDUSTRIAL APPLICABILITY

During operation of the construction machine (not shown), a significantamount of vibration is experienced within the frame assembly 14. Themethod of mounting 33 the hood assembly 18 to the frame assembly 14utilizes the bolt assembly 46 to substantially eliminate vibrationtransfer from the frame assembly 14 to the hood assembly 18.

The bolt assembly 46 is manufactured so that the adhesive 124 is appliedto the second portion 150 of the upper surface 132 of the second bevelwasher 128 until it is adjacent and substantially coplanar with thefirst portion 140 and substantially fills the first space 120. Theinclination of the second portion 150 of the upper surface 132 of thesecond bevel washer 128 ensures a non-uniform thickness of the adhesive124 within the first space 120. Since the thickness of the adhesive 124increases as the distance from the longitudinal axis 70 of the bolt 50increases, the bolt assembly 46 is capable of withstanding maximumbending loads occurring at the longitudinal axis 70 due to theflexibility of the adhesive 124 at the thicker portions. The thicknessof the adhesive 124 may be controlled through variations in the lengthof the first portion 140 of the upper surface 132, the length of thesecond portion 150 of the upper surface 132 and the inclination of thesecond portion 150 from the first portion 140. Additionally, the use ofthe adhesive 124 within the first space 120 acts as a damping source tovirtually eliminate the vibration transfer from the frame assembly 14 tothe hood assembly 18. Damping capabilities may be controlled through thetype of adhesive 124 used and the number of bevel washers within thewasher assembly 54. The lower planar surface 104 of the first bevelwasher 96 is seated on the first portion 140 of the upper surface 132 ofthe second bevel washer 128 so that the first portion 146 of the lowerplanar surface 104 of the first bevel washer 96 and the first portion140 of the upper surface 132 of the second bevel washer 128 are incontact and so that the second portion 156 of the lower planar surface104 is in contact with the adhesive 124. The adhesive 124 is applied tothe second portion 116 of the upper surface 100 of the first bevelwasher 96 until it is adjacent and substantially coplanar with the firstportion 108 in the same manner as the adhesive applied to the secondbevel washer 128. The lower planar surface 88 of the flat washer 80 isseated on the first planar portion 108 of the upper surface 100 of thefirst bevel washer 96 so that the first portion 114 of the lower planarsurface 88 of the flat washer 80 and the first portion 108 of the uppersurface 100 of the first bevel washer 96 are in contact and so that thesecond portion 122 of the lower planar surface 88 of the flat washer 80is in contact with the adhesive 124. The adhesive 124 is then cured inany suitable manner between the washers 80,96,128 to bind the washers80,96,128 together thereby defining the washer assembly 54. Once cured,the washer assembly 54 is placed on the frame assembly 14 so that thelower surface 136 of the second bevel washer 128 is placed on the uppersurface 22 of the frame assembly 14. The lower surface 38 of themounting flange 32 of the hood assembly 18 is brought into contact withthe upper surface 84 of the flat washer 80. The hole 43 in the mountingflange 32, the opening 56 in the washer assembly 54 and the tapped bore30 within the frame assembly 14 are coaxially aligned so that the bolt50 may be threaded through the openings 43,56,30 and into the tappedbore 30 to secure the structural assembly 10 in a conventional manner toachieve appropriate torque requirements. The contact area of the planarsurfaces 84,114,108,146,140,136 of the washers 80,96,128, the upperplanar surface 22 of the frame assembly 14 and the upper and lowerplanar surfaces 34,38 of the mounting flange 32 of the hood assembly 18allow for adequate abutment of the bolt 50 to achieve proper torquerequirements during assembly.

In view of the above, the use of an adhesive between washers in a boltassembly provides a simple and inexpensive shock absorber with dampingcapabilities between two components in a construction machine tosubstantially eliminate vibration transfer between the components. Theadhesive is spaced a predetermined distance from a longitudinal axis ofa bolt and has a non-uniform thickness which increases as the distancefrom the longitudinal axis increases to provide protection from bendingloads about the axis. The washers and adhesive form a washer assemblywith damping and flexibility characteristics controlled throughvariations in the design.

What is claimed is:
 1. A bolt assembly, comprising:a flat washer havingupper and lower planar surfaces defining an opening therethrough; abevel washer having upper and lower surfaces defining an openingtherethrough when positioned with a first planar portion of the uppersurface of the bevel washer adjacent and in contact with the lowersurface of the flat washer, a second portion of the upper surface of thebevel washer diverging outwardly a predetermined distance toward thelower surface of the bevel washer to define a space between the lowersurface of the flat washer and the second portion of the upper surfaceof the bevel washer, the opening of the bevel washer being coaxial withthe opening of the flat washer; a bolt having a longitudinal axis, anelongated body portion extending through the openings in the flat washerand the bevel washer and a head portion seated against the upper surfaceof the flat washer; and an adhesive disposed within the space betweenthe lower surface of the flat washer and the second portion of the uppersurface of the bevel washer.
 2. The bolt assembly of claim 1, whereinthe adhesive is disposed a predetermined distance from the bolt axiswithin the space between the lower surface of the flat washer and thesecond portion of the upper surface of the bevel washer and has apredetermined non-uniform thickness.
 3. The bolt assembly of claim 1,wherein the flat washer and the bevel washer are radially shaped.
 4. Thebolt assembly of claim 2, wherein the flat washer and the bevel washerare rectangularly shaped.
 5. A washer assembly, comprising:a flat washerhaving upper and lower planar surfaces defining an opening therethrough;a bevel washer having upper and lower surfaces defining an openingtherethrough when positioned with a first planar portion of the uppersurface of the bevel washer adjacent and in contact with the lowersurface of the flat washer, a second portion of the upper surface of thebevel washer diverging outwardly a predetermined distance toward thelower surface of the bevel washer to define a space between the lowersurface of the flat washer and the second portion of the upper surfaceof the bevel washer, the opening of the bevel washer being coaxial withthe opening of the flat washer; and an adhesive disposed within thespace between the lower surface of the flat washer and the secondportion of the upper surface of the bevel washer.
 6. A method ofmounting first and second components to substantially eliminatevibration transfer therebetween, comprising the steps of:applying anadhesive to a first inclined portion of an upper surface of a bevelwasher; attaching a flat washer defining an opening therethrough at afirst portion of a lower surface to a second planar portion of the uppersurface of the bevel washer which defines an opening therethrough sothat a second portion of the lower surface of the flat washer is incontact with the adhesive and the upper surface of the bevel washer andthe openings of the bevel washer and the flat washer are coaxiallyaligned; allowing the adhesive to cure between the second portion of thelower surface of the flat washer and the first portion of the uppersurface of the bevel washer to bind the flat washer and the bevel washertogether thereby defining the washer assembly which defines a jointopening therethrough; placing the washer assembly on an upper surface ofthe second component so that the joint opening of the washer assembly iscoaxially aligned with a defined opening within the second component;aligning a lower surface of the first component with the upper surfaceof the second component and contacting the lower surface of the firstcomponent with an upper surface of the washer assembly so that a definedopening through the first component is coaxially aligned with the jointopening in the washer assembly and the opening within the secondcomponent; threading an elongated body portion of a fastener with alongitudinal axis through the openings of the first component and thewasher assembly and into the opening within the second component until ahead portion of the fastener seats against a portion of an upper surfaceof the first component and the first component, second component andwasher assembly are securely attached; vibrating the second component;and damping the vibration from the second component within the adhesivein the washer assembly so that vibration from the second component issubstantially not transferred to the first component.
 7. The method ofmounting first and second components to substantially eliminatevibration transfer therebetween as set forth in claim 6, wherein thestep of applying the adhesive includes the step of:applying the adhesivea predetermined distance from the longitudinal axis of the fastener.